Since you did qualify "amateur", good until scuffed via cart path or trees. Also abrasions from high-spinning shots. Discolorations from gently tapping trees does not affect performance.

Play it until you scuff it up or it gets discolored enough that you want to pull a new ball out of the bag.

I play mine until the forest snatches it up,or for some strange reason the ball decided it wants to swim.:)

I say its personal preference, just recently i played 1 ball for six rounds..YES KIDS 432 HOLES. I couldn't lose it, i hit it in the trees find it, hit it in the water just within reach with my buddies ball retriever. Cart path yep found .It became a running joke after the third round. It was cut , scrapped dingy, Titleist was fading.. I lost it on an 200 yd iron shot on the 18th hole. When i lost it i was a little sad.. I say use it until it stops performing...madgolfer. hitem straight ......

Play 'em to you loose 'em.

I think it all depends on the individual. One of my paying pals uses a sleeve each round. Me, I may play a ball a couple of rounds, but normally, if it looks good, I play it. If I am playing in a tournament, I may only use one ball during a round unless it gets mark/scuff on it.

Until it's scuffed. If it makes a double or above it goes in timeout too.

I agree with most. Keep playing it until there are too many scuffs during regular play. During tournament play I replace them more frequently and save the slightly scuffed for regular play.

Until it loses the sheen and starts picking up dirt/mud because the sheen is gone. usually about 72 holes.

Assuming the ball I start with makes it through to the 18th green, I use one ball for a round. If it survives and still looks good, rolls out well and doesn't seem to have lost any distance, it's the ball of choice for the next 18; however, after the second round, it's time for it to join the shag bag, IMO.